Optical fibers made of glass are often used in optical transmission systems and other optical systems. The machining of the end face of these fibers plays a crucial role during the use of these monomode or multimode fibers. It is important that the end faces have a particularly uniform surface so that the transition from one fiber end to another or to an active element can be carried out with damping values which are as low as possible. It is also important that the end faces of the fibers can be produced at predetermined angles and that these angles are reliable and reproducible.
Various mechanical processes are currently known for severing optical fibers. With these processes, the fiber is typically fixed in a holding device consisting of two holders which are then mutually offset, for example, so that the correct angle is ensured during the cutting operation (see, e.g., EP 351,225.) To effect the cut, a tradition cleaving mechanism such as a diamond cutter is used. It is also known to twist the fiber or begin to cut and then break the fibers along the partial cut. After the fiber is cut, its end face is then polished to minimize optical losses.
The mechanical approach of cleaving and polishing a fiber has a number of significant shortcomings. For example, the multiple steps required makes this approach time-consuming, and, thus, expensive. The approach of mechanically cleaving and polishing a fiber also tends to be limited in flexibility. For example, ribbon cable can be cut only under limited conditions. Furthermore, the angle of the end face of a fiber is generally limited to less than 15° due to the excessive forces the polishing pad imparts to the fiber as the angle increases. As used herein, the phrases “angle of the end face” and “end face angle” refer to the angle from a perpendicular of the optical axis of the fiber. As the end face angle increases, the axial force component of the pad on the fiber increases. Glass fiber tends to lack axial strength. At some point, the axial force component, in combination with the torsional force component, causes the fiber tip to fracture. Although this point various depending upon the polishing technique, the end face angle is generally below 15°.
Therefore, there is a need for preparing the end face of a glass fiber which is inexpensive, versatile, and not limited to certain end face geometries. The present invention fulfills this need among others.